Medical access devices such as intravenous catheters, feeding tubes for total parental nutrition (TPN) and the like have long been used in treatment of hospitalized patients. Historically, the actual penetration device was a rigid metal needle and the usage was almost exclusively on patients who were substantially confined to bed. The confinement to bed or at least the immobilization of a limb where the catheter was placed was necessitated because nearly any movement of the rigid metal needle would cause some trauma to the blood vessel or organ where the device was placed.
The development of biocompatible polymeric materials led to the development of many types of flexible medical access devices such as peripheral intravenous catheters, central intravenous catheters, feeding tubes, drains and the like formed from the flexible materials. Since these devices are flexible, a degree of movement of the body around the catheter generally does not result in significant trauma to the organ or blood vessel like that caused by movement of rigid steel needle devices. As medical practitioners became more comfortable with the flexible medical access devices, they began to allow patients with catheters more freedom of movement. Additionally, since the newer flexible devices caused less trauma, practitioners began to leave the devices in place for longer and longer periods. Devices are now available that are usable for fully ambulatory patients that are living at home and not hospitalized. As a result, patients with medical access devices are exposed to many more opportunities to cause physical damage to their devices. Additionally, pediatric, uncooperative or disturbed patients may also disrupt a fluid delivery set and cause physical damage to their medical access device.
There are reports in the literature of physical damage to peripheral intravenous catheters caused by active patients inadvertently catching the fluid line on an object or confused patients damaging their catheter. These reports include physical disruption of medical access devices by a tripping accident, an ill-advised movement or as a result of an confused patient's thrashing about. Commonly used medical tubing sets incorporate polyvinylchloride (PVC) tubing to connect fluid reservoirs and infusion pumps to medical access devices, i.e., catheters and the like. This PVC tubing commonly has a break-force of about ten kilograms or more. A force of about three kilograms removes the tape from the skin when a common taping technique for securing a catheter is used. Catheters also often are secured to the skin with sutures. At the least, a force applied to the sutures would cause significant discomfort to the patient. When an accidental force is applied to the PVC tubing set, the tubing generally does not break, instead it often transfers the force to the medical access device. The force possibly pulls the device off or out of the patient, or worse yet, breaks it off, possibly leaving a portion of the device inside the patient. The soft silicone rubber tubing, in sizes commonly used in catheters for long term implantation, has a break force of less than about one kilogram. Representative of reports in the medical literature regarding difficulties with long-term catheter placement is a paper by Markel and Reynen in the J. Intraven. Nurs. 13(6), 1990; pp347-351, that reports a study of catheter usage experience. Bauch et al. in the J. Paren. and Ent. Nutr. 15(2), 1993; pp175-177, report on the difficulties of retrieval of a portion of a broken-off catheter.
Since the usage of long-term implantation catheters in fully ambulatory patients is now common, more and more patients are potentially being exposed to situations where they may cause physical damage to their catheters while the catheters are being used for fluid infusion. Thus, a disconnect device that detaches the tubing set from the patient when a force is applied to the tubing that potentially could physically disrupt the implanted device would provide a benefit to the field of infusion therapy. Such a disconnect device is described below.